Enhancing Oil Recovery in High-Water-Cut Reservoirs: Branched-Preformed Particle Gel Three-Phase Foam Stability and Rheological Properties

Foam flooding is a common method to improve the recovery efficiency of high-water-cut reservoirs, but traditional foam is limited by poor plugging ability and low displacement efficiency. A three-phase foam system has strong stability and can improve the displacement effect of high water cut reservoirs. In this study, the effects of three different particles (branched-preformed particle gel (B-PPG), gelled dispersion, and polymer microspheres) on foam stability were compared. The effects of different particles on the viscosity, viscoelasticity, and thixotropy of the foam were analyzed. In addition, the flow properties in porous media and the displacement effects of B-PPG foam were examined using microscopic visualization experiments. The results showed that B-PPG and the surfactant had good compatibility, and the foam composite index (FCI) of B-PPG foam was better than those of the other two foams at the same particle mass concentration. Even under high-temperature and high-shear conditions, the viscosity of the B-PPG foam consistently surpassed those of the gelled dispersion foam and polymer microsphere foam, demonstrating superior temperature and shear resistance. Notably, the storage modulus (G′) and loss modulus (G″) of the B-PPG foam were greater than those of the other two particle foams. With increasing B-PPG mass concentration, the linear viscoelastic region (LVR) of the foam increased, and the loss factor (tan δ) approached 1. At this time, the foam showed solid-state characteristics; thus, increasing the B-PPG mass concentration could effectively improve the viscoelasticity of the foam. Microscopic visualization experiments revealed that the B-PPG foam changed the fluid path and expanded the swept volume by bridging and direct plugging. Moreover, its high viscoelasticity could improve oil flow and increase oil recovery by 25.7%. The results showed that B-PPG foam had significant advantages in expanding the swept volume and improving the displacement efficiency. Therefore, this study provides a new technical reference for the exploitation of high-water-cut reservoirs.